Occupational Safety and Health Administration. A regulatory office of the U.S. Department of Labor.

An aneroid barograph designed to record atmospheric pressure variations of very small magnitude.

An instrument which measures the effective terrestrial radiation. See Angstrom pyrgeometer.

The smallest change in the environment that causes detectable change in the indication of an instrument. Compare to sensitivity.

A type of anemometer in which the rotation of an element serves to measure the wind. Rotation anemometers are divided into two classes; those in which the axis of rotation is horizontal, such as the windmill anemometer, and those in which the axis of rota ...

That part of snow melt that reaches stream channels as runoff.

A set of rules or conventions used to standardize data transfer between devices.

A coating of ice, generally clear and smooth. formed by the freezing of supercooled water on a surface.

A polariscope consisting of a specially constructed double plate polarizer and a tourmaline plate analyzer. Polarized light passing through the instrument is indicated by the presence of parallel colored fringes, while unpolarized light results in a unifo ...

Capacity of a soil or other surface to be penetrated by water sinking into the ground under the force of gravity. It thus expresses the rate of percolation.

To free something from the binding action of ice by warming it to a temperature above the melting point of ice. Also, a warm spell when ice and snow melt.

Video Display Terminal. An input and display device which includes a keyboard and a screen and allows a human to communicate with a computer.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

The direction, with respect to magnetic north, from which the wind is blowing. Distinguish from true wind direction.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

A small anemometer with flat vanes which indicates the number of linear feet or meters of air which have passed the instrument during its exposure.

The degree of conformity of an indicated value to an accepted standard value, or ideal value. See accuracy rating, measured accuracy.

A system of physical units based upon the use of the meter, the metric ton (106 grams), and the second as elementary quantities of length, mass, and time, respectively.

An instrument which determines the black-body temperature of a substance by measuring its thermal radiation.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.